Mom's children are fighting over her money. Where should I turn for an outside voice to end this fighting?

My mom is 85 years old and running out of money. I am her married daughter - age 56 and in charge of her finances. She does not have a pension, nor did my dad. The house is paid for but was in rundown condition and needed a lot of repairs. My dad was never gainfully employed and my mom has had to work for the last 40 years. My dad retired from being a handyman at the age of 55 - over 30 years ago. Mom had an inheritance of $30,000 that grew into $60,000 over the course of 30 years. I have handled all of the family financial decisions for the last 10 years. My dad was sick and ended up in a nursing home 4 years ago and I applied for and got them on title 19 (after being denied and then reapplying). Dad died 2 years ago. My older divorced brother, age 58 moved in with our mom and was supposed to pay rent of $400.00 per month but didn't for the first 18 months. He claims he didn't understand the arrangement. He works full time and is very active with his social life on the weekends and is not a companion for mom. However, he has done a lot of work around the house and makes it safe for mom to live at home. My husband and I have worked beside him on most of these home repairs. A sister, age 51 moved in also 8 months ago and was supposed to pay rent but doesn't. She buys my mom's food and makes her one meal a day. She also drives her to the doctor, etc. She works 30 hours per week. The problem is mom pays all of the bills including taxes on the house (6,000 per year), heat, electric, telephone, cable and the internet. Mom's unemployment is running out in 3 months. She worked up until age 84. I tried to prepare the family for the loss in income 7 months ago but it just resulted in a big screaming scene where my sister accused me of spending all of mom's money (on house repairs, including a dangerous mold and water problem) to insure a better inheritance for myself. Basically, she said that if I didn't spend down mom's money, she wouldn't be in a position of running out of money. Its a catch 22 situation. In order to stay in the house, repairs had to be made. Nothing was spent that wasn't necessary. The garage was falling down, I was going to apply for a reverse mortgage but the bank officer told me that the condition of the house would be a problem. I am in charge of the money, have tried to move mom to assisted living but her request was to stay in the home. In order to stay in the home it had to be safe and money had to be spent. How do I get my siblings to understand that they need to pitch in more money in order to live in a nice 3 bedroom house with all utilities covered for them? This has put a big strain on the family relationship because I am constantly asking them how much they've paid mom lately, and asking them to pay more, and they think I am meddling in their business. However, my mom pays for the internet and doesn't use it - it's for my brother and sister. Come on, where can any person live for $400.00 a month (or for the cost of groceries) and have everything they need taken care of for them? My siblings have both been known to come home after work and tell mom that she shouldn't talk to them because they need peace and quiet!! After the last fight (Christmas day - of course) my mom got so upset that she decided to take the money responsibility away from me because it is hard on our relationship and she thinks the bill paying is stressing me out. I am stressed by what I consider to be free loaders (and they are my siblings) taking advantage of mom. I want them to pay more money to help out. They don't see it as free loading. They see it as providing a service for mom, and they both are providing a service. However, Mom's money will be gone in less than one year and will not have enough money for the 2012 house taxes. Who can mediate this for the family? My job was to take care of mom's finances. I was pointed the POA. Trying to do the best for mom is driving a wedge between me and my siblings. In order to make peace, I could just stop asking them to help out but in one year there will be a crisis. Any advice?